1. Field of the Invention
The present invention relates to a method and equipment for control of fuel and air to be supplied to an internal combustion engine comprising a fuel-reforming device.
2. Description of the Prior Art
It is known that when an internal combustion engine is supplied with a hydrogen-containing gas from a fuel-reforming device, a very "lean" combustion is made possible, thereby reducing the harmful exhaust gas. For the purpose of reforming the fuel, the so-called partial oxidation method, in which the air and hydrocarbons are made to react on the catalyst bed under the condition of very little air, is often adopted. According to this method, the ratio of air to fuel to be supplied to the fuel-reforming device and the air excess rate in the engine have their optimum values. For the purpose of optimizing these two values, various methods of electrical or mechanical control have been employed.
Although the conventional method of electrical control is capable of relatively accurate control, it leaves much to be improved because it requires a complicated, bulky apparatus including a feedback circuit. When the ratio of air to hydrocarbons to be delivered to the fuel-reforming device is mechanically controlled by means of the carburetor, the apparatus can be made less bulky than in the electrical method. Under the condition of extremely little air, for example, the weight ratio of air to hydrocarbons being less than 3, only unreliable and rough control can be made. This adverse effect emerges in the air excess rate of the engine which has a direct bearing on the harmful contents of the exhaust gas or the fuel consumption rate.